Added isCollectionLike() and isMap() to TypeInformation interface.

isCollectionLike() allows identifying element containers like Arrays, Collections or everything else implementing Iterable.

spring-data-commons-core/src/main/java/org/springframework/data/util/TypeDiscoverer.java

@@ -113,7 +113,9 @@ class TypeDiscoverer implements TypeInformation {
       }
 
       TypeInformation propertyInformation = getPropertyInformation(fieldname);
-      fieldTypes.put(fieldname, propertyInformation);
+      if (propertyInformation != null) {
+        fieldTypes.put(fieldname, propertyInformation);
+      }
       return propertyInformation;
     }
 
@@ -144,6 +146,15 @@ class TypeDiscoverer implements TypeInformation {
     return resolveType(type);
   }
   
+  /* (non-Javadoc)
+   * @see org.springframework.data.util.TypeInformation#isMap()
+   */
+  @Override
+  public boolean isMap() {
+    Class<?> rawType = getType();
+    return rawType == null ? false : Map.class.isAssignableFrom(rawType);
+  }
+  
   /* (non-Javadoc)
    * @see org.springframework.data.util.TypeInformation#getMapValueType()
    */
@@ -157,12 +168,22 @@ class TypeDiscoverer implements TypeInformation {
     return createInfo(parameterizedType.getActualTypeArguments()[1]);
   }
   
+  /* (non-Javadoc)
+   * @see org.springframework.data.util.TypeInformation#isCollectionLike()
+   */
+  @Override
+  public boolean isCollectionLike() {
+   
+    Class<?> rawType = getType();
+    return rawType == null ? null : rawType.isArray() || Iterable.class.isAssignableFrom(rawType);
+  }
+  
   /* (non-Javadoc)
    * @see org.springframework.data.util.TypeInformation#getComponentType()
    */
   public TypeInformation getComponentType() {
     
-    if (!(Map.class.isAssignableFrom(getType()) || Collection.class.isAssignableFrom(getType()))) {
+    if (!(Map.class.isAssignableFrom(getType()) || isCollectionLike())) {
       return null;
     }
     

spring-data-commons-core/src/main/java/org/springframework/data/util/TypeInformation.java

@@ -1,5 +1,6 @@
 package org.springframework.data.util;
 
+import java.lang.reflect.Array;
 import java.util.Collection;
 import java.util.Map;
 
@@ -20,6 +21,15 @@ public interface TypeInformation {
    * @return
    */
   TypeInformation getProperty(String fieldname);
+
+  /**
+   * Returns whether the type can be considered a collection, which means it's a container of elements, e.g. a
+   * {@link Collection} and {@link Array} or anything implementing {@link Iterable}. If this returns {@literal true} you
+   * can expect {@link #getComponentType()} to return a non-{@literal null} value.
+   * 
+   * @return
+   */
+  boolean isCollectionLike();
   
   /**
    * Returns the component type for {@link Collection}s or the key type for {@link Map}s.
@@ -27,6 +37,14 @@ public interface TypeInformation {
    * @return
    */
   TypeInformation getComponentType();
+
+  /**
+   * Returns whether the property is a {@link Map}. If this returns {@literal true} you can expect
+   * {@link #getComponentType()} as well as {@link #getMapValueType()} to return something not {@literal null}.
+   * 
+   * @return
+   */
+  boolean isMap();
   
   /**
    * Will return the type of the value in case the underlying type is a {@link Map}.